System and method for anchoring air separation unit structures to concrete foundations

ABSTRACT

A system and method for anchoring a cold box structure of an air separation unit to a concrete foundation is provided. One such embodiment provides a concrete foundation having a plurality of reinforced concrete piers projecting vertically from a top surface of the concrete foundation and configured to anchor the cold box structure to the reinforced concrete piers using a plurality of horizontally disposed anchor bolts. Alternatively, the concrete foundation may include a plurality of hollow steel structures projecting vertically from a top surface of the concrete foundation and configured to anchor the cold box structure.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to U.S.provisional patent application Ser. No. 62/772,817 filed on Nov. 29,2018, the disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The present invention relates generally to construction techniques forair separation plants, and more particularly to various systems andmethods to secure air separation plant structures, such as a cold boxstructure, to concrete foundations as well as provide horizontalstability to the air separation plant structures.

BACKGROUND

Nationally recognized building codes require that structures orequipment used in an air separation plant such as cold box structures besecured to the foundation to safeguard against the destructive upliftingand shearing forces of seismic events and severe weather related events,i.e., strong winds, tornadoes, hurricanes, etc. The securing of such airseparation plant structures and equipment is typically accomplished byconnecting the frame of the structure or equipment to a concretefoundation through the use of steel anchor bolts embedded in theconcrete foundation. The required thickness of the foundation andembedment depth of the anchor bolts are generally determined inaccordance with the American Concrete Institute (ACI) Building CodeRequirements for Structural Concrete (ACI 318-14). Anchor bolts aretypically laid out in the foundation prior to pouring concrete, withthreaded portions sticking up out of the concrete foundation high enoughto be secured by a round washer and a nut. When the concrete dries, theanchor bolts would be used to secure the frame of the structure to theconcrete foundation.

However, due to the large size of structures used in most air separationplants, conventional designs and procedures for anchoring such largestructures to concrete foundations as described in ACI 318-14 Chapter 17are not directly applicable. For example, many air separation plantshave cold box structures that have a side dimension or diameter that canrange from 10 feet (10′) to 17 feet (17′) and the height of such coldbox structures can be up to 300 feet (300′). To secure such largestructures to the on-site casted concrete foundation, very large sizeanchor bolts are typically used. Such large anchor bolts may range up tosix inches (6″) in diameter with an embedment depth of six feet (6′)feet or more, whereas design using ACI 318-14 Chapter 17 is generallylimited to anchors with four inch (4″) diameter and less. Some failuremodes associated with anchoring of such large structures of an airseparation plant with very large anchor bolts include pull-out or steelfailure from excessive tensile loadings as well as concretebreakout/pryout, punching shear failures and steel failures fromexcessive shear loadings.

What is needed, therefore, is an improved method and system for securingair separation plant structures or equipment to reinforced concretefoundations without the use of traditional anchor bolts.

SUMMARY OF THE INVENTION

The present invention may be characterized as a system for fastening aframe of a cold box structure of an air separation plant to a concretefoundation, the system comprising: (i) a concrete foundation having aplurality of reinforced concrete piers projecting vertically from a topsurface of the concrete foundation, wherein the reinforced concretepiers are arranged to project vertically from the top surface of theconcrete foundation at locations adjacent to the outer perimeter of thecold box structure; (ii) a plurality of anchor bolts, each anchor boltcomprising an anchor bolt body having a first end and a threaded secondend, with both ends configured to be projecting from the one of theplurality of the reinforced concrete piers in an orthogonal orientationto the vertical projection of the one of the plurality of reinforcedconcrete piers from the top surface of the concrete foundation, whereinthe threaded second end of each of the one or more anchor bolts areconfigured to pass through a bore on a frame of the cold box structure;and (iii) one or more nuts configured to screw onto the threaded secondend of each anchor bolt body to fasten the frame of the cold boxstructure to the plurality of reinforced concrete piers.

The present invention may also be characterized as a hollow steelstructure assembly for fastening a cold box structure of an airseparation plant to a concrete foundation, the hollow steel structureassembly comprising: one or more hollow steel structures, each hollowsteel structures comprising a body defining a central axis, a lengthmeasured along the central axis and a width or diameter measuredorthogonally to the central axis, the body further defining a first endconfigured to be embedded in the concrete foundation, and a second endconfigured to be projecting from the concrete foundation. The second endof the one or more hollow steel structures are configured to projectfrom a top surface of the concrete foundation and further configured toproject into the frame of the cold box structure. In some embodiments,the body of each of the one or more hollow steel structures may be atapered configuration.

An alternative arrangement of the hollow steel structure assembly forfastening a cold box structure of an air separation unit to a concretefoundation provides the one or more hollow steel structures each havingone or more alignment holes in the body proximate the second end. Insuch alternate embodiment, the second end of the one or more hollowsteel structures are configured to project from a top surface of theconcrete foundation and project adjacent to the outside perimeter of thecold box structure. The assembly would further include one or moreanchor bolt assemblies configured to traverse through the alignmentholes proximate the second end and couple the one or more hollow steelstructures to the frame of the cold box structure in a horizontalorientation.

BRIEF DESCRIPTION OF THE DRAWINGS

While the present specification concludes with claims distinctlypointing out the subject matter that Applicants regard as theirinvention, it is believed that the invention will be better understoodwhen taken in connection with the accompanying drawings which:

FIG. 1 depicts a concrete foundation having a plurality of reinforcedconcrete piers suitable for use in an embodiment of the present systemand method for anchoring air separation unit structures to concretefoundations;

FIG. 2 depicts an air separation unit cold box structure being anchoredonto a concrete foundation having the reinforced concrete piers of FIG.1;

FIG. 3 depicts an air separation unit cold box structure being anchoredonto a concrete foundation having a plurality of hollow steel structuresembedded therein in accordance with another embodiment of the presentsystem and method for anchoring air separation unit structures toconcrete foundations;

FIG. 4 is a perspective view of an embodiment of the hollow steelstructure suitable for use in the present system and method foranchoring air separation unit structures to concrete foundations;

FIG. 5 is a perspective view of an alternate embodiment of the hollowsteel structure suitable for use in the present system and method foranchoring air separation unit structures to concrete foundations; and

FIG. 6 is a perspective view of yet another embodiment of the hollowsteel structure suitable for use in the present system and method foranchoring air separation unit structures to concrete foundations.

DETAILED DESCRIPTION

Reinforced Concrete Piers

Turning to FIG. 1 and FIG. 2 of the drawings, there is shown anarrangement of reinforced concrete piers 20 used to secure structures orequipment of an air separation plant such as cold box structures 10 to areinforced concrete foundation 15. As seen therein, reinforced concretepiers 20 are disposed on the concrete foundation in a configuration suchthat multiple sides of the cold box structure 10 are aligned with andadjacent to the reinforced concrete piers 20. Horizontally anchoring thecold box structure 10 of the air separation plant to the reinforcedconcrete piers 20 via aligned holes 25 in the cold box structure and thereinforced concrete piers 20 is used in lieu of the conventional meansfor anchoring cold box structures, namely using large-size verticallyoriented cast-in-place anchor bolts.

Use of the reinforced concrete piers 20 for anchoring cold boxstructures 10 eliminates the need to design a complicated anchor boltchairs for the large size vertical anchor bolts and simplifies thecalculations for determining connection or anchoring strength.Additional advantages arising from the use of the reinforced concretepiers 20 include likely reduction in the thickness of the concretefoundation 15 when compared to concrete foundations where anchoring isaccomplished using large-size vertical cast-in-place anchor bolts. Thisreduction in concrete foundation thickness is primarily a result of asmaller required embedment depth of the reinforcement of the concretepiers 20 and the monolithic nature of the pure concrete arrangement ofthe foundation and piers.

The concrete piers 20 preferably have a plurality of reinforcing barsembedded therein to provide sufficient longitudinal and transversereinforcement to the pier and to confine the concrete when formed.Aligned horizontal thru-holes 25 are also placed in the reinforcedconcrete piers 20 as well as the cold box structure 10 to facilitateconnection using horizontally disposed anchor bolts (not shown).

Hollow Steel Structures (HSS)

Turning now to FIGS. 3-6 of the drawings, there is shown variousconfigurations of hollow steel structures 40 configured to be embeddedin concrete foundations 35 and used to anchor cold box structures 30 orequipment of an air separation unit to a concrete foundation 35. As seenin one embodiment, the hollow steel structures 40 are vertically cast-instructures disposed at the corners and/or around the perimeter of wherethe cold box structure 30 is to be placed on the concrete foundation.The hollow steel structures 40 are used to connect the cold boxstructure 30 to the foundation 35 in lieu of the conventional means foranchoring cold box structures, namely using large-size verticalcast-in-place anchor bolts.

In various embodiments of the hollow steel structures shown in FIGS.4-6, the one or more hollow steel structures 40 comprise a body 42defining a central vertical axis, a length measured along the centralvertical axis and a width or diameter measured orthogonally to thecentral vertical axis. The hollow steel structure body 42 includes afirst end 44 configured to be embedded in the concrete foundation 35 anda second end 46 configured to be projecting vertically upwards from theconcrete foundation 35. The projecting second end 46 of the hollow steelstructures 40 are configured to project into corresponding receptaclesin the frame of the cold box structure 30.

The hollow steel structures 40 may optionally include a steel plate 50(See FIG. 4) or other reinforcing structure 52 (See FIG. 5) affixed tothe body 42 proximate the first end 44 and extending in an orthogonalorientation to the central vertical axis of each of the one or morehollow steel structures 40. The steel plate 50 or other reinforcingstructure 52 are configured to be embedded in the concrete foundation35. Also, in some embodiments, the body 42 of each of the one or morehollow steel structures may be a tapered configuration as shown in FIG.6 so as to slide into and engage corresponding receptacles in the bottomof the cold box structure 30.

Although the present arrangement for securing cold box structures orequipment of an air separation plant to a reinforced concrete foundationhas been discussed with reference to one or more preferred embodiments,as would occur to those skilled in the art that numerous changes andomissions can be made without departing from the spirit and scope of thepresent invention as set forth in the appended claims.

What is claimed is:
 1. A system for fastening a frame of a cold boxstructure of an air separation plant to a concrete foundation, thesystem comprising: a concrete foundation having a plurality ofreinforced concrete piers projecting vertically from a top surface ofthe concrete foundation, wherein the reinforced concrete piers arearranged to project vertically from the top surface of the concretefoundation at locations adjacent to the outer perimeter of the cold boxstructure; a plurality of anchor bolts, each anchor bolt comprising ananchor bolt body having a first end and a threaded second end, with bothends configured to be projecting from the one of the plurality of thereinforced concrete piers in an orthogonal orientation to the verticalprojection of the one of the plurality of reinforced concrete piers fromthe top surface of the concrete foundation; wherein the threaded secondend of each of the one or more anchor bolts are configured to passthrough a bore on a frame of the cold box structure; and one or morenuts configured to screw onto the threaded second end of each anchorbolt body to fasten the frame of the cold box structure to the pluralityof reinforced concrete piers.
 2. A hollow steel structure assembly forfastening a cold box structure of an air separation plant to a concretefoundation, the hollow steel structure assembly comprising: one or morehollow steel structures, each hollow steel structures comprising a bodydefining a central axis, a length measured along the central axis and awidth or diameter measured orthogonally to the central axis, the bodyfurther defining a first end configured to be embedded in the concretefoundation, and a second end configured to be projecting from theconcrete foundation; wherein the second end of the one or more hollowsteel structures are configured to project from a top surface of theconcrete foundation and further configured to project into the frame ofthe cold box structure.
 3. The hollow steel structure assembly of claim2 further comprising a steel plate or other reinforcing structureaffixed to the body proximate the first end and extending in anorthogonal orientation to the central axis of each of the one or morehollow steel structures, the steel plate configured to be embedded inthe concrete foundation.
 4. The hollow steel structure assembly of claim2 wherein the body of each of the one or more hollow steel structures isa tapered configuration.
 5. A hollow steel structure assembly forfastening a cold box structure of an air separation plant to a concretefoundation, the hollow steel structure assembly comprising: one or morehollow steel structures, each hollow steel structures comprising a bodydefining a central axis, a length measured along the central axis and awidth or diameter measured orthogonally to the central axis, the bodyfurther defining a first end configured to be embedded in the concretefoundation, and a second end configured to be projecting from theconcrete foundation, and one or more alignment holes in the bodyproximate the second end; wherein the second end of the one or morehollow steel structures are configured to project from a top surface ofthe concrete foundation and further configured to project adjacent tothe outside perimeter of the cold box structure; and one or more anchorbolt assemblies configured to traverse through the alignment holesproximate the second end and couple the one or more hollow steelstructures to the frame of the cold box structure in a horizontalorientation.
 6. The hollow steel structure assembly of claim 5 whereinportions of the one or more hollow steel structures are filled withconcrete.
 7. The hollow steel structure assembly of claim 5 furthercomprising a steel plate affixed to the body proximate the first end andextending in an orthogonal orientation to the central axis of each ofthe one or more hollow steel structures, the steel plate configured tobe embedded in the concrete foundation.
 8. The hollow steel structureassembly of claim 7 wherein the size of the steel plate is selected suchthat a perimeter of the steel plate is between about 0.25 times theembedment depth of the body to about 4.0 times the embedment depth ofthe body.
 9. The hollow steel structure assembly of claim 7 wherein thesteel plates of the one or more hollow steel structures provide punchingshear reinforcement to the concrete foundation proximate the one or morehollow steel structures.
 10. The hollow steel structure assembly ofclaim 7 wherein the steel plates of the one or more hollow steelstructures are further configured to be disposed below a longitudinalreinforcement within the concrete foundation.